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Date: Fri, 20 Apr 2018 22:01:34 +0200
From: Boris Brezillon <boris.brezillon@bootlin.com>
To: Ladislav Michl <ladis@linux-mips.org>
Cc: linux-kernel@vger.kernel.org, linux-mtd@lists.infradead.org, Boris
 Brezillon <boris.brezillon@free-electrons.com>, Peter Ujfalusi
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 Schaller" <hns@goldelico.com>, Andreas Kemnade <andreas@kemnade.info>
Subject: Re: [PATCH v2] mtd: onenand: omap2: Disable DMA for HIGHMEM buffers
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Hi Ladislav,

On Mon, 16 Apr 2018 08:52:59 +0200
Ladislav Michl <ladis@linux-mips.org> wrote:

> dma_map_single doesn't get the proper DMA address for vmalloced area,

That's not true, it returns the right DMA (physical) address, it's just
that:

1/ the memory location is not necessarily physically contiguous
2/ in case your arch is VIVT ot VIPT, there may be several entries in
   the cache pointing to the same physical location, and the cache
   maintenance operations done by dma_map_single() will only operate on
   one of these entries.

> so disable DMA in this case.
> 

The fix looks good though. Can you rephrase your commit message to make
it clearer.

Thanks,

Boris